Hello,

I'm not good in Physics, but I really want to learn. I'm just to slow to understand... So my question is, can anyone teach me for free about Physics?

Thank you,
decent

Oh, please! Post your questions, post your work like I told you earlier!


1. A 1600-kg car is moving at 20 m/s northward. A cement delivery truck with a mass of 2500 kg moving at 35 m/s southward collides head-on with the car. If they move together after collision, what is their common velocity?

2. A 25-g ball moving southward at 30 m/s collides with a 10-g ball moving along the same line with a velocity of 15 m/s southward. After collision, the 25-g ball attains a velocity of 22 m/s southward. What is the velocity of the 10-g ball?

Use the law of conservation of momentum; m_1u_1 + m_2u_2 = m_1v_1+m_2u_2

m_1 being the mass of the first body
m_2 the mass of the second body
u_1 the initial velocity of body 1
u_2 the initial velocity of body 2
v_1 the final velocity of body 1
v_2 the final velocity of body 2

m_1u_1 is the initial momentum of the first body
m_2U_2 is the initial momentum of the second body
m_1v_1 is the final momentum of the first body
m_2v_2 is the final momentum of the second body

m_1u_1 + m_2u_2 is the sum of initial momenta
m_1v_1 + m_2v_2 is the sum of final momenta

I cannot spoon-feed you all the time! It's time to work! Post your answers.